Self-purging proportioning pump for corrosive liquids



Dec. 13, 1966 A. s. LIMPERT ETAL 3,291,055

SELF-PURGING PROPORTIONING PUMP FOR CORROSIVE LIQUIDS Filed Aug. 2. 19654 Sheets-$heet 1 11W wil I [11M 13, 1966 A. s. LIMPERT ETAL. 3,291,055

SELFPUHGING PROPORTIONING PUMP FOR CORROSIVE LIQUIDS 4 Sheets-Sheet 2Filed Aug. 2, 1965 Dec. 13, 1966 A. s. LIMPERT ETAL 3,291,055

SELFPURGING PROPORTIONING PUMP FOR GORROSIVE LIQUIDS Filed Aug. 2. 19654 Sheets-Sheet 5 FIG. 3

Dec. 13, 1966 A. s. LIMPERT ETAL 3,291,055

EL -PURGING PROPORTIONING PUMP FOR CORROSIVE LIQUIDS Filed Aug. 2. 19654 Sheets-Sheet 4 FIG 5 United States Patent O 3,291,055 SELF-PURGINGPROPORTIONING PUMP FOR CORROSIVE LIQUIDS Alexander S. Limpert and RobinJ. Limpert, both of 1121 S. Clinton Ave, Bay Shore, N.Y. Filed Aug. 2,1965, Ser. No. 478,029 19 Claims. (Cl. 103-44) This is acontinuation-in-part of U.S. application Serial No. 351,719 filed March13, 1964, now abandoned.

This invention relates to self-purging proportioning or metering feedpumps and more particularly to a hydraulically actuated proportioningfeed pump especially designed for the proportioning of corrosiveliquids.

Proportioning feed pumps are used to feed and meter liquids of alltypes. Chemical reactions, for instance, frequently require that smallquantities of chemicals be supplied thereto at predetermined rates, andsuch pumps are used for this purpose. In most cases, the liquids fed areblended with a feed flow or substrate, which blend then serves as thereaction medium.

U.S. Patent No. 2,869,467 describes and claims a proportioning feed pumphaving a diaphragm actuated by hydraulic pressure, the pressure requiredfor actuation being obtained through the action of a rotating andreciprocating piston operating in a cylinder. On the pressure stroke ofthe reciprocating piston, a volume of oil is pumped to a diaphragm in anamount determined by the length of the stroke, and this increased volumeof oil causes flexing of the diaphragm, due to the increased pressure ofthe oil on that side. On the return stroke, the pressure is relieved,and the diaphragm can return to its initial position. Thus,reciprocation of the piston induces periodic flexing of the diaphragm.The other side of the diaphragm communicates with a pumping chamber ofthe proportioning feed pump that forms part of the liquid pumpingsystem, and the flexing action of the diaphragm is used to pump theliquid in that chamber.

The length of the stroke of the reciprocating piston can be adjusted tocontrol the amount of oil fed to the diaphragm, and thereby control therate of feed of liquid by the pump. A compression spring in the pumpingor diaphragm chamber returns the diaphragm to its normal position aftereach flexing action, when the return stroke of the reciprocating pistonexhausts the oil in the hydraulic chamber that causes flexing of thediaphragm.

The piston and cylinder are so arranged that on the return stroke thepressure is relieved by venting the interior of the cylinder to an openreservoir. The cylinder is submerged in a reservoir of oil, which isopen to the atmosphere; on the return stroke the piston opens a vent inthe cylinder, thereby suddenly decreasing the pressure in the cylinderand in the hydraulic side of the diaphragm to atmosphere. On thepressure stroke, the vent is closed by the piston.

Patent No. 3,100,451 describes an improvement on this type of pump, tomake it possible to use a double diaphragm construction with opposeddiaphragms having a single compression spring therebetween, to distendthe diaphragms in the quiescent condition when a hydraulic pulse is notbeing applied thereto, and thus assist in filling the pump chamber onthe back stroke of the pump, thereby avoiding the need for negativepressure in the hydraulic system. This type of construction has thedisadvantage that the compression spring is exposed to the liquids beingpumped, and when these liquids are corrosive rapid wear results, as wellas contamination of the liquid being pumped with the material corrodedaway from the spring.

Diaphragm pumps of the above types are usually used where extremeaccuracy is required for the metering of liquids. However, the pumps ofthe prior art have often been plagued by problems of inaccuracy whichhave seemed insolvable. Often, the pumps have had to be shut down forrepairs after relatively short onstream times due to continuedinaccuracy in metering which could not be corrected by the operatorswhile the pumps were in operation.

In accordance with the invention, it has now been determined that onesource of such inaccuracy is the accumulation of air or other gases inthe hydraulic system or pumping chamber of the pumps. The inventionaccordingly provides means for purging the hydraulic system as well asthe pumping chamber of gas periodically during operation.

The deleterious effect of even a small amount of gas in the system canbe illustrated by a unit designed to pump 0.5 cc. per stroke. In thissituation, an air bubble with a volume of 0.1 cc. at atmosphericpressure in the hydraulic chamber would have a significant effect on theaccuracy of the pump.

In accordance with the present invention, an improved hydraulicallyactuated proportioning feed pump is provided having means for ventingthe hydraulic system regularly during operation, comprising, incombination, a housing having therein a pumping chamber, a hydraulicchamber, a flexible diaphragm forming at least a portion of a wallseparating the chambers, and adapted to flex from a normal positionoutwardly into the pumping chamber under pressure of hydraulic fluid inthe hydraulic chamber; pulsing means for cyclically supplying hydraulicfluid under pressure to the topmost portion of the hydraulic chamber andfor exhausting hydraulic fluid therefrom, valve means for venting thehydraulic system to the atmosphere during the exhaust portion of thecycle, and bias means within the hydraulic chamber for returning thediaphragm after distention by hydraulic fluid toits normal positionduring the exhaust portion of the cycle.

There are also fluid inlet and outlet connections in the pumping chamberon the other side of the diaphragm, for supplying fluid to be pumped anddelivering fluid pumped by pulsation of the diaphragm; the outletconnections preferably are connected at the topmost portion of thepumping chamber so that any gases accumulating in the pumping chambercan migrate thereto and be swept out of the outlet with the pumpedfluid.

Preferably, the pulsing means is a piston pump having means to supply oneach pressure stroke of the piston a known volume of hydraulic fluid tothe hydraulic chamber to distend the diaphragm. The preferred pump is anadjustable reciprocating piston pump of the type shown in U.S. PatentNo. 2,869,467, discussed above. In that pump, on each suction stroke ofthe piston, the cylinder is vented to a reservoir of oil which in turnis vented to the atmosphere. Any air or other gases which may collect inthe hydraulic chamber of the diaphragm pump is thereby swept out of thecylinder into the reservoir and then to the atmosphere. The fact thatthe pumping cylinder is immersed in a reservoir of oil prevents anyadditional air from entering the hydraulic chamber during the venting.Pulsing systems other than reciprocating piston pumps are also suitablefor use in the invention, such as a rotary piston pump. The hydraulicsystem of these pumps includes the hydraulic chamber of the diaphragm,any conduits connecting that chamber to the pulsing means, and usually,the pulsing means itself.

The invention contemplates means for creating turbulence in thehydrauiic system, to aid in sweeping out all of the gas bubbles from thehydraulic chamber. For example, the diaphragm bias means can createadditional turbulence as it snaps the diaphragm back to its normalposition, when the pressure is released in the hydraulic chamber.Accordingly, by combining a diaphragm pump having a bias means locatedon the hydraulic side of the pump diaphragm, a hydraulic connectionlocated at the highest part of the hydraulic chamber, and provision forventing the hydraulic system to atmosphere on the exhaust portion of thecycle, a self-purging metering pump with a high degree of accuracy canbe obtained. By placing the outlet from the pumping chamber at thehighest point in the pumping chamber, that chamber is also effectivelykept clear of gases.

To further ensure that all gas is purged from the hydraulic system, thetotal volume of the fluid connection between the hydraulic chamber andthe pulsing means preferably is less than the volume of the pressurepulse provided by the pulsing means.

The proportioning pumps of the invention can include a plurality ofdiaphragms, in the manner, for example, shown in U.S. Patent No.3,100,451. The pumping chamber or alternatively, the pulsing orhydraulic chamber, can, for example, be in the form of a cylinder,closed at each end by an impermeable flexible diaphragm, with the biasmeans always in the pulsing or hydraulic chamber or chambers. In thecase of a double diaphragm pumping chamber, the tension bias means isplaced outside the diaphragms, and the hydraulic liquid is supplied tothe hydraulic chambers outside the diaphragms, as in FIGURE 5. In thecase of a double diaphragm hydraulic chamber, the tension bias means isplaced between the diaphragms and the hydraulic liquid is supplied tothe chamber therebetween for flexing action of the diaphragms in thepumping chambers, as in FIGURE 5. In such a structure, two differentliquids could be pumped, and one diaphragm could be stopped (anadjustable stop can be used) so that the other receives a pressureeffect of a proportion of the volume of hydraulic fluid supplied, thetotal amount of this fluid in turn being adjusted by the effectivestroke of the piston. If but one liquid is to be pumped, the valves maybe manifolded so that a single outlet could be used.

The bias means is of the tension or compression type depending upon theposition of the hydraulic chamber and the direction of the bias forcerequired. Any form of bias means can be used. Coil springs, disksprings, also known as Belleville springs or washers, and resilientbushings or plugs are typical, and various embodiments thereof are shownin the drawings. These can be made of any suitable material, usuallymetal, such as stainless steel, carbon steel, nickel, brass and bronze,or plastic, such as rubber, synthetic rubber, polyamides, polypropylene,polyvinyl butyral, or metal coated with any inert plastic material.

The diaphragms employed in the proportioning pumps of the invention canbe made of any sheet material which is sufficiently flexible andresilient to be flexed under fluid pressure, and which can be returnedto normal nonflexed position when the fluid pressure is relieved, aided,in accordance with the invention, by bias means. Desirably, thediaphragm can withstand many millions of such flexures without damage.

For additional strength, the sheet diaphragm can be provided with abacking material or plate which will prevent damage due tooverpressuring, and can also serve to control the amount of flexureunder a given fluid pressure. The backing material can support all oronly a part of the diaphragm surface exposed to fluid pressure.

In addition, to increase flexibility, a diaphragm may be formed as acomposite or multiple ply structure. Two or more flexible sheets, of thesame or different material, may be laminated or clamped together to formthe diaphragm. If the sheets are laminated, they may be joined togetherwith an adhesive material, by welding or any other suitable means. Theuse of a laminated or clamped structure of very thin sheets, increasesthe flexibility of a diaphragm of a given resiliency, thereby allowingfor a greater range of flexing on each stroke of the diaphragm. In thecase of plural diaphragms, the

diaphragms can all be laminated, or only one can be laminated, asdesired. The laminated diaphragm can be designed to have the same or adifferent resiliency than a single ply diaphragm.

The configuration of the diaphragms can be selected according to thepumping requirements. For instance, the diaphragm can be of uniformthickness throughout its area. It can also be designed to be thicker atthe center than at the periphery, so as to increase its resistance toflexing. The shape of the diaphragm is quite immaterial, and thediaphragm can be circular, elliptical, polygonal, rectangular, square orindeed any shape, according to the design of the hydraulic or pulsingand pumping chambers. Thus, for example, the diaphragms can be made ofsheet metal, such as stainless steel, Monel metal, aluminum, copper,carbon steel, brass, tin, nickel and zinc, or of a resilient plasticsheet material such as rubber, synthetic rubber, neoprene, Viton A,urea-formaldehyde, melamine-formaldehyde, phenol-formaldehyde,polymethylmethacrylate, nylon, polystyrene, polytetrafluoroethylene,polytrifluorochloroethylene, polypropylene, polyethylene, polyvinylchloride, polyvinylidene chloride and polycarbonate resins, and epoxyresins; and glass fiber-reinforced laminates of any of these materials.

The back-up plates or other materials used, if desired, forreinforcement can be made of the same or different materials. Thus, forinstance, a stainless steel diaphragm can be supported by a stainlesssteel plate or by a plastic plate, and a rubber diaphragm can bereinforced by a stainless steel plate or by a plate made ofpolytetrafluoroethylene or nylon. These are merely illustrativeexamples, and other combinations will be apparent to those skilled inthe art from the above description.

The pulsing or hydraulic fluid can be selected as desired, according tothe bias means employed, and will be inert to the bias means, thediaphragm and hydraulic chamber walls. Any hydraulic fluid can be used.The hydraulic fluid can, for example, be a lubricating oil or othernoncorrosive petroleum liquid, a silicone oil, or a polyalkylene glycolether.

The drawings show several preferred embodiments of the invention.

FIGURE 1 is a top view of a complete feed pump in accordance with theinvention, including in a single unit a diaphragm pump and a hydraulicpulsing unit for supplying hydraulic fluid to the diaphragm for flexingand pumping action thereof.

FIGURE 2 is a cross-sectional view of the pump of FIGURE 1, taken alonglines 22 and looking in the direction of the arrows.

FIGURE 3 is a cross-sectional view of a modification of the pump ofFIGURE 2, showing a rubber plug bias means.

FIGURE 4 is a cross-sectional view of an embodiment of dual diaphragmfeed pump in accordance with the invention, showing the hydraulicchambers and the pumping chamber thereof.

FIGURE 5 is a cross-sectional view through an embodiment employing adouble diaphragm at opposite ends of a single hydraulic chamber tooperate two pumping chambers.

FIGURE 6 is an elevation view of a complete feed pump in accordance withthe invention wherein the diaphragm pump and pulsing means are separateunits.

Throughout the drawings, like numbers are used for like parts.

The combination pump shown in FIGURES 1 and 2 includes in a singlecasing a diaphragm pump section A and a reciprocating piston pumpsection B, or hydraulic pulsing means for providing hydraulic pulses tothe diaphragm. The piston pump is an improved embodiment of the pumpdescribed in the above mentioned US. Patent No. 2,869,467, as shown inFIGURE 8 thereof. The combination pump is enclosed by an outer casingformed in three sections: a pump section 1, a motor section 2, and adiaphragm pump head 3. Sections 1 and 2 are bolted together by bolts 5,passing through the flanges 6. Gasket 9 forms a fluid-tight seal betweenthe two sections. The diaphragm head 3 is bolted to the side of section1 by bolts 8. Within sections 1 and 2 is a chamber 10 which constitutesa reservoir, for the oil supply for both pumps.

Drive motor is mounted on plate 16 by slotaheaded bolts 18. Pump section1 is a unitary casting in this embodiment, and has formed therein ahydraulic cylinder 20, a hydraulic diaphragm chamber 21 and a fluidconnection or passage 23 from the cylinder to the hydraulic chamber 21.A piston 25 is reciprocatingly and rotatably disposed within thecylinder 20, and has a driving arm 28 secured to the end thereof. Thearm passes through an aperture 29 in a ball 30, which is mounted betweenthe arms 32 of the coupling 35. Coupling 35 is driven by the motor 15 bymeans of the shaft 37. A second position of the ball 30, coupling 35,arms 32 and piston 25 is shown by the dotted lines in the drawing. Thepiston 25 has a longitudinal slot 27 extending a sutficient length toregister with the port 26 during the exhaust stroke of the piston. Theslot coincides with port 26 through the cylinder 20, serving to vent thehydraulic system as described in US. Patent No. 2,869,467.

In order to regulate the volume of hydraulic fluid supplied by thepiston on each stroke, the length of the column of oil pumped by thepiston is adjusted by means of the slave piston 40, which isreciprocatingly held within the top portion of cylinder 20. Snap ring41, is held in a groove in cylinder 20 above the fluid connection 23 andbelow the piston 40, and acts as a stop to limit the downward movementof the piston.

The cylinder has an open end piercing the casing section 1, and closedoif by cylinder head 45, inserted in the open end in a press fit andheld there by locking screw 46. The head has a threaded central channel,in which is held the bolt 44, which extends into the cylinder into aposition to engage the slave piston at the upper limit of its travel.Micrometer head 47 is slip-fitted onto the splined top of bolt 44. Byturning micrometer head 4-7, the bolt 44 is rotated in its threadedsocket, and thus moved up or down in the cylinder, to adjust the travelof slave piston 40.

Compression coil spring 50 bears against the upper surface of the piston46 and against the lower or inner surface of the cylinder head 45,biasing the slave'piston 40 against the snap ring 41.

The variable stop means described above as a micrometer screw adjustmentis merely one possible type. Other stop adjustments can be used of thecontinuously variable and discontinuously variable types, as will beevident to anyone skilled in this art.

The oil reservoir 10 for the hydraulic system also The venting means inaccordance with the invention,

vents the hydraulic system during each exhaust stroke of the piston andcomprises a vent plug 52 having central passage 53, opening at one endto the topmost portion of the reservoir chamber 10 and at the other endto the atmosphere, and the port 26, which connects the cylinder 20 withthe chamber 10. Thus, any gases vented through port 26 are vented to theatmosphere via chamber 10 and passage 53. Because the port 26 is onlyindirectly connected to the atmosphere in this way, on the return strokeof the piston, when the piston slot 27 is lined up with port 26, ventingis into the oil reservoir 10, thereby preventing any air from enteringthe port 26, while any gases that bubble up through the reservoir 10 cannonetheless escape to the atmosphere. The aligning of slot 27 with theport 26 is determined by the rotation of the piston as it reciprocates.The piston is reciprocated and rotated by means of the drive arm 28. Asthe coupling 35 is rotated by the motor 15, the arm 28 is rotatedtherewith and also slides back and forth within aperture 29. The slot isso arranged that when the piston is on the exhaust stroke, it is alignedwith port 26. A fuller explanation of the general principles ofoperation of the piston pump can be had in Patent No. 2,869,467.

To further ensure that all gas is thoroughly exhausted from thehydraulic system, the conduit 23, connecting the hydraulic chamber 21 ofthe diaphragm pump to the cylinder 20 has a total volume substantiallyless than that of the cylinder 20. This is rather simple to arrange inthe single unit compact structure shown in FIGURES 1 and 2.

The pumping section A includes the hydraulic or pulsing chamber 21 and apumping chamber 65 which are separated by a diaphragm 63. The pumpingchamber 65 which is defined by the diaphragm 63 and pump head 3, isprovided with an inlet 67 and an outlet 68. The hydraulic outlet 68 islocated at the highest point of the pumping chamber to ensure that anygas in the chamber will be swept out with the pumped fluid and not beaccumulated. The hydraulic chamber 21 defined by the interior walls ofthe casing 1 and the diaphragm 63 has a port 24 serving as an inlet andan outlet for the pulsing fluid, in this case, hydraulic oil, via thepassage 23. The port 24 is at the topmost portion of the hydraulicchamber 21. The top wall 70 of the chamber 21 tapers upwardly towardsthe port 24 to ensure that no gas bubbles can be trapped at the top ofthe chamber.

The flexible diaphragm assembly includes the diaphragm 63 which is heldbetween the diaphragm head 3 and the side of casing section 1. Thediaphragm is spring-mounted for return to a normal position, afterflexure, on the exhaust stroke of the piston 25. The spring-mountingassembly includes a flanged nut 79 on the pumping chamber side of thediaphragm threaded on the end of bolt 77. To prevent leakage through thediaphragm, a sealing nut 86 is threaded on bolt 77 on the hydraulicchamber side of the diaphragm, and nuts 79 and 80 clamp on to thediaphragm 63, to form a leakproof seal. At the far end of bolt 77 is thebolt head 83.

The compression coil spring for diaphragm return is held between aperforated back-up plate 72, also clasped at its periphery between thehead 3 and easing section 1, and the spider 82, which is fitted betweenbolt head 83 and back-up plate 72. One perforation in the back-up plate72 is aligned with port 24. Thus, whenever the diaphragm 63 is flexedoutwardly into the pumping chamber 65, such movement is against theaction of the spring 85, which tends to pull the diaphragm back in thedirection of the hydraulic chamber. As a result, as soon as the pulsingfluid pressure tending to force the diaphragm outwardly is released, thespring 85 pulls the diaphragm 63 back to the normal nonflexed positionshown in FIGURE 1. The spring 50 must be weaker than the bias means inthe hydraulic chamber 21, otherwise the diaphragm would be flexed beforethe slave pis ton would move.

The inlet and outlet 67, 68, respectively, of the pump ing chamber areprovided with appropriate check valves 87 and 88, either mechanically orelectrically operated, or operated by fluid pressure in the pumpingchamber, to control the flow of fluid through the pumping chamber, inthe direction from the inlet 67 to the outlet 68. Thus, under increasein pressure in chamber 65, valve 87 is adapted to close and valve 88 toopen, and on reduction in pressure, as when diaphragm 63 is returned tonormal position by spring 85, valve 87 is adapted to open and valve 88to close. Annular seal rings 90 and 91, respectively, ensure a leakproofseal when the valves 87 and 88 are closed. Inlet and outlet lines 98 and99,

respectively, are threadedly attached to pump head 3 in fluid flowconnection with valves 87 and 88, respectively.

Valves 87 and 88 are held in valve chambers formed in pump head 3, whichare in turn sealed by threaded screws 92 and 93.

In operation, the hydraulic pulsing means B is adjusted to periodicallysupply a predetermined volume of pulsing liquid or hydraulic fluid, inthis case oil, through the line 23 to the hydraulic chamber 21. Theincrease in fluid volume and hence fluid pressure in the hydraulicchamber 21 causes the diaphragm 63 toflex outwardly into the pumpingchamber 65, against the action of the spring 85. This results in acorresponding displacement and increase of pressure of the fluid in thepumping chamber. Valve 87 closes in response to the increase in fluidpressure in the pumping chamber 65, while the valve 88 opens, and thus,the diaphragm forces fluid displaced in the chamber 65 to flow outthrough the outlet 68.

The operation of the hydraulic pulsing means B is such that eachdelivery of a volume increment of hydraulic fluid to the line 23 isfollowed by a period when fluid is withdrawn from the line and cylinder20 is vented to the reservoir through port 26 and the slot in the piston25, resulting in a decrease in fluid pressure in the line and in thehydraulic chamber 21 to atmospheric. As soon as the pressure in chamber21 is reduced sufficiently, the force of the spring 85 can overcome thefluid pressure in the chamber, and retract the diaphragm 63 to theposition shown in FIGURE 1. In this position, as is evident from thedrawing, the perforated plate 72 serves as a stop and prevents furthermovement of the diaphragm beyond the limiting position shown. Thediaphragm is now ready for the next successive flexing and resultantpumping cycle.

Whenever the diaphragm 63 is withdrawn from its flexed position, uponreduction of pressure in the hydraulic chamber 21, under action of thespring 85, the valve 88 is closed, and the valve 87 is opened,permitting entry of fluid into the pumping chamber 65 past the valve 87and through the inlet 67. Thus, the volume of fluid in the chamber isnow brought up to equal the volume of the chamber, as before, andanother pumping cycle can begin.

By adjustment of the volume of fluid delivered to line 23 and of thepulsing period of the hydraulic pulsing means, it will be apparent thata continuous timed pumping and consequent delivery of any desired volumeof fluid from the pumping chamber 21 can be assured.

The diaphragm, while sweeping the hydraulic fluid out of the hydraulicfluid chamber also sweeps any air or other compressible gases which maybe trapped in the hydraulic chamber out of the port 24 to the hydraulicpump where they are vented through the port 26 to the oil reservoir. Inthe case of the coil spring as used in the present embodiment, theaction of the spring induces an added turbulence in the hydraulic fluidwhich aids in sweeping out any more bubbles of gas which otherwise couldtend to cling to any surface.

The feed pump shown in part in FIGURE 3 is similar in every respect tothat of FIGURE 1 with the exception of the bias means; consequently, thefollowing discussion is limited to this feature.

The coil spring is replaced by a resilient rubber plug 100 which is heldbetween a washer 101 attached onto the bolt 83 and the back-up plate 72.Thus, as the diaphragm is moved outwardly under increased fluid pressurein the pulsing chamber 21, the rubber plug 100 is compressed.Accordingly, when the pressure in the pulsing chamber 21 is relieved,the diaphragm is returned to the normal position shown in FIGURE 3, andthe pumping cycle can then be repeated, as in the case of the feed pumpof FIGURES 1 and 2.

The pump shown in FIGURE 4 is a single unit device similar to that shownin FIGURES 1-3 except that it is provided with a pair of diaphragms 63and 63 and a pair of hydraulic chambers 21 and 21', respectively, bothacting on a single pumping chamber 65.

The pump of FIGURE 4 comprises a casing section 1 forming a firsthydraulic chamber identical to that shown in FIGURE 1. An annular plate117 forms the side Walls of the pumping chamber 65' and is provided witha hydraulic fluid conduit 23. Outlets 112 are located in the uppermostportion of the plate 117 and inlets 113 in the lowermost part. Passages120 and 121 leading from the inlet valve 87 and outlet valve 88',respectively, are attached to fluid lines not shown. Otherwise, theconstruction and operation of these valves are the same as in FIGURES 1and 2.

Hydraulic chamber head 110 defines one end and the side walls of thesecond hydraulic chamber 21' and is provided with hydraulic fluidconduit 23". The two diaphragms 63 and 63 form the end walls separatingthe pumping chamber 65' from the hydraulic chambers 21 and 21',respectively. The diaphragm 63, plate 117, diaphragm 63 and head 110 areattached to the casing section 1 by means of bolts 5'. The diaphragmsare provided with bias means 85 and 85' and spiders 82 and 82',identical to those in FIGURE 1. Diaphragm 63 is shown in this embodimentas a composite diaphragm formed of two sheets clamped together betweenflanged nut 79' and sealing nut 80.

A stop 125 is provided on spider 82'. As diaphragm 63' flexes inwardlyinto the pump chamber 65', drawing the bolt 77 and spring with it, thestop eventually encounters back-up plate 72, after which furthermovement of the diaphragm 63' is prevented. This prevents the diaphragm63 from taking more than its share of the pulse volume of hydraulicfluid delivered to the inlet port 23, and insures an appropriateproportional response of the diaphragm 63 to this pulse. Thus, whenequal hydraulic oil pressure is applied simultaneously in chambers 21and 21', to the faces of the diaphragms 63 and 63', respectively, thestopped diaphragm 63 moves towards the stop and then halts, while anyadditional motion is taken by the diaphragm 63.

It is understood that the spring 85 is heavier than the spring 85'. Thisensures that most of the pulsing movement initially will be taken bydiaphragm 63, which has the weaker spring. The heavier spring 85 ondiaphragm 63 controls movement of this diaphragm after diaphragm 63' hasreached its stopped or limiting position.

The result is that in this structure the pumping action applied to thefluid in the pumping chamber 65' is continued over a longer interval bythe two diaphragms 63 and 63 acting more or less in sequence.

Thus, in operation, when hydraulic fluid is supplied under pressure tothe hydraulic chambers 21 and 21', the diaphragms 63 and 63' are pushedoutwardly in that sequence, the diaphragm 63 moving first to its stopinto the pumping chamber 65 and pulling shaft 83' with it against theforce of spring 85', up to its stop, and then the second diaphragm 63moves against the stronger spring 85.

When the pulse is ended, and the pressure in chambers 21 and 21 isreduced to atmospheric, the diaphragms 63 and 63' are returned to theirnormal positions by the springs 85 and 85'. The spring 85 being theheavier, diaphragm 63 is returned to its normal position the first, anddiaphragm 63 follows shortly thereafter.

It will further be noted that this sequential action prevents ahydraulic lock. If the volume of hydraulic oil delivered to the pulsingchambers 21 and 21 is insufficient to bring the stopped diaphragm 63' toits locking or limiting position, then the unstopped diaphragm 63 willscarcely move at all. It is only when the hydraulic pulse is ofsuflicient volume to bring the stopped diaphragm to its stop that theunstopped diaphragm moves on whatever additional hydraulic oil volumeremains.

Diaphragms 63 and 63' may also be made of different sizes and hydrauliclock will be avoided because the hydraulic pressure operating on thelarger diaphragm will overcome the spring force first, even if thesprings themselves are the same size. The same effect can be achieved byusing diaphragms of different resiliencies and different thicknesses.

Thus, for instance, the diaphragms can be of different materials,whether the thickness be the same or different. One diaphragm can bemade of stainless steel, and the other diaphragm made ofpolytetrafiuoroethylene, or of rubber, both of which are more resilientthan stainless steel, and will therefore flex more readily at a lowerpressure. The diaphragm which is flexed at the lower pressure is thestopped diaphragm, as in the structure of FIGURE 4, and the diaphragmwhich flexes only at a higher pressure need not be stopped. Differencesin resiliency or flexing pressure can also be obtained or compensatedfor as desired by using springs of different force, or stressing thesprings to different force positions. Similar effects can be obtained byvarying the surface areas of the diaphragms exposed to fluid pressure inthe hydraulic chamber, the pumping, or both.

A plurality of double diaphragm pumps of the type shown in FIGURE 4 maybe used in parallel, with all diaphragms stopped except one, and thatone having the least resilient diaphragm or spring, and with a commoninlet and outlet line for supplying and delivering the liquid to bepumped, and a common line to the pulsing unit so that all diaphragms areactuated by the same pulse. The diaphragm pumps can also be single, ifdesired, with all diaphragms stopped except one, and that one having theleast resilient diaphragm or spring.

The coupling of a plurality of pumping units to a single delivery linecan be employed to supply the same volume of fluid through the outletline at a greatly increased pressure. Also, a greater total volume canbe pumped at a lower pressure. When the total volume is that which wouldbe delivered by one pumping unit, the three units can be made of smallervolume, and therefore much stronger, so that a single pump can be usedto pump fluids at extremely high pressures, of the order of severalthousand p.s.i. or more.

A plurality of pumps of the type shown in FIGURE 4 can be used in serieswith a common outlet and inlet valve. In this case no sump valves areneeded for the individual pumps, flow being through all pumps from inletto outlet. A common hydraulic feed line would be provided so that thehydraulic pulsing fluid is supplied to all of the hydraulic pulsingchambers simultaneously.

The pump shown in FIGURE 6 is provided with a pair of diaphragms 203,203, on each side of a single hydraulic chamber 201, each acting againstseparate pumping chambers 204 and 204. Return of the diaphragms tonormal position, as shown in FIGURE 6, is assured by use of a singletension coil spring 206.

The pump of FIGURE 6 has an annular central plate 207 defining the sidewalls of the hydraulic chamber 201, with two diaphragms 203 and 203defining the end walls thereof. The diaphragm 203 has a lesser thicknessthan diaphragm 203' and thus is flexed under a lesser pressure inchamber 201 than is diaphragm 203. A pair of outer back-up plates 208and 208f are held to the central plate 207 by six bolts 210. A pair ofinner back-up plates 237 and 237' are provided in the hydraulic chamber201 having perforations 238 and 238. One of the perforations in each ofplates 237 and 237' is aligned with conduits 229 and 229', respectively.The back-up plates 208 and 208 are provided with ports 214, 215, checkvalves 217, 210 and inlet and outlet lines 220, 221. Plate 207 isprovided with port 225 connected to line 226 and to conduits 227 leadingto the hydraulic or pulsing chamber 201. The tension coil spring 206 ishooked into the shafts 230, 230, which are anchored on diaphragms 203and 203, respectively. Shaft 230 is 10 provided with a stop 231 to limitmovement of the diaphragm 203.

As diaphragm 203 flexes outwardly, drawing the shaft 230 and spring 206with it, the stop 23]. eventually encounters back-up plate 237, afterwhich further movement of the diaphragm 203 is prevented. This preventsthe diaphragm 203 from taking more than its share of the pulse volume ofhydraulic fluid delivered to the inlet ports 225, and ensures anappropriate proportional response of the diaphragm 203' to this pulse.Thus, when hydraulic oil pressure is applied to chamber 201, to thefaces of the diaphragms 203 and 203', simultaneously, the stoppeddiaphragm 203 moves towards the stop and then halts, while anyadditional motion is taken by the diaphragm 203'.

The result is that in this structure the pumping action is applied tothe fluids in the pumping chamber 204 and 204', the diaphragms actingmore or less in sequence.

Thus, in operation, when hydraulic fluid is supplied under pressure tothe hydraulic chamber 201, the diaphragms 203 and 203 are pushedoutwardly, in that sequence, the thinner diaphragm 203 moving first toits stop 231 into the pumping chamber 204, and pull shafts 230 and 230'with them against the force of spring 206.

When the pulse is ended, and the pressure in chamber 201 is reduced toatmospheric, the diaphragms 203 and 203 are returned to their normalpositions by the spring 206. The diaphragm 203' being the heavier,diaphragm 203 is returned to its normal position the first, anddiaphragm 203 follows shortly thereafter.

It will further be noted that this sequential action prevents ahydraulic lock. If the volume of hydraulic oil delivered to the pulsingchamber 201 is ll'lSlllTlClEllt to bring the stopped diaphragm 203 toits locking or limiting position, then the unstopped diaphragm 203' willscarcely move at all. It is only when the hydraulic pulse is ofsufficient volume to bring the stopped diaphragm to its stop that theunstopped diaphragm moves on whatever additional hydraulic oil volumeremains.

It will also be apparent that by this action the same or differentvolumes of the same or different fluids can be pumped in chambers 204and 204. By adjustment of the position of stop 231, and the total volumeof oil pulsed to chamber 201, any relative volumes can be delivered, aswill be apparent, and the same or different fluids can be supplied tothe chambers 204 and 204' for any desired combination of fluids andfluid volumes.

The diaphragm pump of FIGURE 6 is operated by a separate pulsing meansof the type shown in FIGURE 5.

The pulsing unit of the proportioning feed pump of FIGURE 5 has a base327 to which are attached a motorrotated fly wheel 312, connected by ayoke 313 to an adjustable self-venting hydraulic pulsing mechanism 314of the type described in U.S. Patent No. 2,869,467. This hydraulicpulsing mechanism supplies pulsations of hydraulic fluid, such aslubricating oil, having a definite and controlled displacement andperiod to the hydraulic line 226, which in turn conveys them to thediaphragm pumping unit 208.

Having regard to the foregoing disclosure, the following is claimed asthe inventive and patentable embodiments thereof:

1. A self-purging proportioning feed pump comprising, in combination, ahousing having therein a pumping chamber and a hydraulic chamber, aflexible diaphragm forming at least a portion of a wall separating thechambers and adapted to flex from a normal position outwardly into thepumping chamber under pressure of hydraulic fluid in the hydraulicchamber; a fluid port at the highest point of the hydraulic chamber,pulsing means in fluid connection with the fluid port for cyclicallysupplying hydraulic fluid under pressure to the hydraulic chamber andfor exhausting hydraulic fluid from the hydraulic chamber, vent meansfor venting the hydraulic system to the atmosphere only during theexhaust portion of the cycle,

1 1 diaphragm bias means within the hydraulic chamber for returning thediaphragm to a normal position during the exhaust portion of the cycle,and fluid inlet and outlet connections in the pumping chamber forsupplying fluid to be pumped and delivering pumped fluid by flexingpulsation of the diaphragm.

2. The pump of claim 1 wherein the outlet connection to the pumpingchamber is connected at the highest point in the pumping chamber.

3. The pump of claim 2 wherein the pulsing means is a reciprocatingpiston pump.

4. The pump of claim 3 comprising an oil reservoir open to theatmosphere, and wherein the pulsing means comprises a cylinder at leastpartially immersed therein, and wherein the vent means from saidcylinder opens into the oil.

5. A proportioning feed pump according to claim 4 wherein the pulsingmeans comprises a longitudinally reciprocating and rotating main pistonoperating within the cylinder, drive means for said piston, and whereinthe vent means comprises a port through the cylinder to the oilreservoir and a channel in the piston adapted to connect the port to thecylinder space above the piston only during the suction stroke of thepiston.

6. The pump of claim 5 comprising adjusting means to adjust the volumeof fluid pulsed by the piston on each stroke.

7. A proportioning feed pump according to claim 6 wherein the adjustingmeans comprises a slave piston operating within said cylinder in fluidpressure connection with the main piston, piston bias means acting onsaid slave piston pushing it towards said main piston, the piston biasmeans having a lower force than the diaphragm bias means, and variablestop means for varying the length of travel of said slave piston; theslave piston being moved away from said main piston by fluid pressure onthe compression stroke, a distance determined by the variable stopmeans, and towards the piston on the suction stroke by the piston biasmeans.

8. A proportioning feed pump according to claim 3 comprising fluidconduit means between the pulsing means and the hydraulic chamber havinga total volume less than the volume of the hydraulic fluid pulsesprovided by the pulsing means.

9. A feed pump in accordance with claim 1 having a stop associated withthe diaphragm for limiting distention 12 of the diaphragm under pressureof hydraulic fluid in the hydraulic chamber.

10. A feed pump in accordance with claim 1 wherein the diaphragm isformed as a multiple ply structure.

11. A feed pump in accordance with claim 1 having a plurality offlexible diaphragms forming walls of the pumping chamber.

12. A feed pump in accordance with claim 11 in which the diaphragms havedifferent distention characteristics.

13. A feed pump in accordance with claim 11 in which at least one of thediaphragms is provided with a stop limiting distention of the diaphragmunder pressure of hydraulic fluid in the hydraulic chamber.

14. A feed pump in accordance with claim 1 having a plurality offlexible diaphragms forming walls of the hydraulic chamber.

15. A feed pump in accordance with claim 14 in which the diaphragms havediflerent distention characteristics.

16. A feed pump in accordance with claim 1 having a plurality of pumpingchambers and a diaphragm associated with each pumping chamber.

17. A feed pump in accordance with claim 1 in which the bias means is aspring.

18. A feed pump in accordance with claim 17 in which the spring is acoil spring.

19. A feed pump in accordance with claim 17 in which the spring is aresilient plug.

References Cited by the Examiner UNITED STATES PATENTS 250,253 11/1881Johnson 10344 1,101,266 6/1914 Franklin 10344 1,940,516 11/1932 Tennant10344 2,424,595 7/ 1947 Warren 10344 2,444,586 7/ 1948 Wuensch 103-442,675,758 4/1954 Hughes 10344 2,711,134 6/1955 Hughes 10344 2,869,4671/1959 Limpert et al 103-44 2,902,936 9/1959 Bradley 10344 3,100,4518/1963 Limpert et al 103-44 FOREIGN PATENTS 339,136 12/1930 GreatBritain. 480,289 4/ 1953 Italy.

ROBERT M. WALKER, Primary Examiner.

1. A SELF-PURGING PROPORTIONING FEED PUMP COMPRISING, IN COMBINATION, AHOUSING HAVING THEREIN A PUMPING CHAMBER AND A HYDRAULIC CHAMBER, AFLEXIBLE DIAPHRAGM FORMING AT LEAST A PORTION OF A WALL SEPARATING THECHAMBERS AND ADAPTED TO FLEX FROM A NORMAL POSITION OUTWARDLY INTO THEPUMPING CHAMEBR UNDER PRESSURE OF HYDRAULIC FLUID IN THE HYDRAULICCHAMBER; A FLUID PORT AT THE HIGHEST POINT OF THE HYDRAULIC CHAMBER,PULSING MEANS IN FLUID CONNECTING WITH THE FLUID PORT FOR CYCLICALLYSUPPLYING HYDRAULIC FLUID UNDER PRESSURE TO THE HYDRAULIC CHAMBER ANDFOR EXHAUSING HYDRAULIC FLUID FROM THE HYDRAULIC CHAMBER, VENT MEANS FORVENTING THE HYDRAULIC SYSTEM TO THE ATMOSPHERE ONLY DURING THE EXHAUSTPORTION OF THE CYCLE, DIAPHRAGM BIAS MEANS WITHIN THE HYDRAULIC CHAMBERFOR RETURNING THE DIAPHRAGM TO A NORMAL POSITION DURING THE EXHAUSTPORTION OF THE CYCLE, AND FLUID INLET AND OUTLET CONNECTIONS IN THEPUMPING CHAMBER FOR SUPPLYING FLUID TO BE PUMPED AND DELIVERING PUMPEDFLUID BY FLEXING PULSATION OF THE DIAPHRAGM.